There are several threads on the forum about alternators and control boxes but I haven't found a definitive statement advising exactly when the Lucas 8TR controller that initially went with the 15AC alternator on the MK II series (Cooper S, Mini K) was replaced on the production line by the 4TR controller. Does anyone know? Doc has contributed to many of the controller threads so I'm hoping he may be able to help here.

I don't know the changeover date, what I do know is the 4TR is still available in a green Lucas NCB148 box, but the 8TR has gone to the Lucas graveyard..

John Smidt would know, if anybody does...

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

Thanks Doc. I'd like to know which one would have been fitted on the production line to my October 1970 MK II S which currently has a much later alternator with integrated controller. If it was the 4TR then it shouldn't be a problem to acquire the authentic items. If it was the 8TR then I can think about the option of fitting an old 8TR for cosmetic purposes.

don't know dates once again, but I once found an 8TR controller on a very original (but stuffed) lift-up-handles Mini K - its now on my S, and is dated 11/70

I'd be looking for dates on them to find a changeover if I was you

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There's a discussion on the MiniMania website that starts with:

I have a 1970 Australian 1275 Cooper S. It has an alternator with an external voltage regulator with four (4) prongs. The alternator is still working, but the voltage regulator is not. Does anyone know where I can find such a creature?

The voltage regulator has on it:

8TR, integrated electronic control, 062938104 A 6-71, Lucas Australia patented

And the prongs are labeled: B+, +, F, -

So the 8TR was still being manufactured (and presumably fitted to new vehicles) in June 1971. Perhaps the 4TR didn't appear until around the Clubman era? It also confirms the 8TR as a Lucas Australia item.

Simon - do you have a picture of the 8TR? Is it the one with a silver metal base (as opposed to black plastic)?

I have a late 70's MK2 and it has a 4TR on it.

yeah, silver metal base... it's got 8TR cast into the plastic, pretty hard to mistake it

what's the date on your 4TR phillz ?

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Over the many years that I have been involved with Minis, I believe that all Mk2 Cooper s had an 8TR fitted from new, it is my opinion that the 4TR units were fitted as replacements, I am not saying this is Fact, This is based on what I have observed over many years, I have purchased Ex police cars with the 4TR fitted but from memory the manufacture date of the unit did not line up with all other date of manufacture indicators. on those cars.
Personally I would fit the 8TR if possible, I have been told that these can be repaired, However I have not yet found someone to repair them for me

I can't see a date on the unit but the cars 9/70. I don't know if it's original but it looks like it's been there a while,

The Date On The 4TR Is usually stamped on the top of the unit ( looking at the unit fitted to the car ) It is interesting to note that the 4TR was produced in the UK at the same time as the 8TR was produced in Australia

I've got a dead one I keep meaning to give to the guy I work with.... he's an electronics guru and I'm sure he could replicate it in the same packaging

it's even be OK if we had to gut it and put something inside the mudguard with wires going through to make it look original

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John - do you have a theory as to why the ex-Police cars had 4TR's? You wouldn't think the 8TR's would be worn out through use as the cars were sold after 3 months or so. I'm assuming only few had 4TR's and not most - is that right?

I repaired mine a few weeks ago. Didn't have to get too crazy with it however...the spade connectors are connected to the internal electronic wizardry by four braided copper leads. These are spot welded to the spade connectors and often corrode or get vibrated off.

To get to them you remove the tow rivets at the back and it will (literally) fall apart in your hands. The voltage regulator components themselves are immersed in silicone, but can be dug out if you need to. Well worth a looky.

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SooperDooperMiniCooperExpertEngineering

All garage work involves equal measures of enthusiasm, ingenuity and a fair degree of irresponsibility.

It is my opinion that the cars fitted with 4TR units were replaced for one reason or another Most of the police cars had 8TR units, Most times when I ordered 8TR units From Parts & acc I recd 4TR units so I assume that if they were replaced under warranty they could be supplied with a 8TR Unit Or a 4TR

My 1970 cooper s mk2 built 7-70 has the 8tr regulator fitted.It's dated 5-70.
So are you guys saying that the 8tr is no longer available and the 4tr
is a substitute
Regards and merry christmas

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